I need help on what to do with my constipated baby!

So my son has been  constipated for about three weeks, he is currently 5 weeks old, well we've took him to his doctor, and got his formula changed because he was on soy formula and that's what had first caused his constipation, well his doctor prescribed him some medicine to and we've been using Kora Syrup, AND gripe water with infants Tylenol, nothing has worked. He is so miserable, he only poops like 2 times a day and today it's only been once, he is steady crying and he is always kicking and putting his legs up to his adominal and straining and getting red in his face. Should I go to the hospital? what should I do? nothing is working and I feel so bad for him.😔😩